Apparatus for facing and internal turning

Abstract

Apparatus for facing and internal turning includes a rotatable shaft and a turning head fixed for rotation with the shaft. A tool carriage for carrying a cutting tool is displaceable on the turning head transversely to the axis of rotation thereof. The transverse displacement of the carriage is effected by way of two planetary gear units lying in planes at right angles to the axis of rotation of the shaft. The sun gear of the first unit is fixed for rotation with the shaft, whilst the sun gear of the second unit, which acts as a driving gear for the tool carriage, is rotatable relative to the shaft. A further ring gear is disposed coaxially with said gear units and engages a gear connected for rotation with the planet gear of the second unit. Fastening means selectively lock said further ring gear against rotation whereby the sun gear of the second unit is rotated relative to the shaft and effects transverse displacement of the tool carriage.

We claim: 
     
       1. An apparatus for facing and internal turning, the apparatus comprising a stationary casing, a rotatable driven shaft mounted in said casing, a turning head fixed for rotation with said shaft, a tool carriage for carrying a cutting tool displaceable on the turning head transversely to the axis of rotation thereof, and means for effecting the transverse displacement of the tool carriage, wherein said means for effecting transverse displacement of the tool carriage comprise a first and a second planetary gear unit each mounted in a recess in the casing to lie within a respective plane extending at right angles to the axis of rotation of said shaft, each said planetary gear unit comprising a sun gear, a ring gear and at least one planet gear, wherein the sun gear of the first planetary gear unit is fixed for rotation with the shaft, the sun gear of the second planetary gear unit is rotatable relative to the shaft and acts as a driving gear for the tool carriage, and the ring gear of one of said first and second planetary gear units is rotatable in the casing, said means for effecting the transverse displacement of the tool carriage further comprising selectively operable gear means for imparting a rotational speed to the sun gear of the second planetary gear unit which is different from the rotational speed of the sun gear of the first planetary gear unit, said selectively operable gear means comprising at least one further ring gear disposed in said recess in the casing coaxially with said first and second planetary gear units, said further ring gear being rotatable in the casing and having a different number of teeth from that of the ring gears of said first and second planetary gear units, fastening means arranged to selectively lock said further ring gear to said casing, and an additional gear engaged by said further ring gear and connected for rotation with the planet gear of the second planetary gear unit. 
     
     
       2. An apparatus according to claim 1, wherein said further ring gear and said additional gear is disposed between said first and second planetary gear units. 
     
     
       3. An apparatus according to claim 1, wherein two said further ring gears are provided and each is engaged with an associated additional gear, and wherein said further ring gears and said additional gears are disposed between said first and second planetary gear units. 
     
     
       4. An apparatus according to claim 1, wherein said fastening means for the further ring gear comprises a detent plate which is pivotally mounted in the casing and which is arranged to engage in toothing provided on the outer periphery of the further ring gear. 
     
     
       5. An apparatus according to claim 4, wherein said detent plate is prestressed by spring means such that if the tool carriage is overloaded the detent plate is disengaged from the toothing of the ring gear.